The peak rate of a Long Term Evolution-Advanced (LTE-A) system is greatly improved compared with that of a Long Term Evolution (LTE) system, to meet the requirements of downlink 1 Gbps and uplink 500 Mbps. At the same time, the LTE-A system is required to have good compatibility with the LTE system. Based on the demand of improving the peak rate, being compatible with the LTE system and fully utilizing spectrum resources, Carrier Aggregation (CA) technology is introduced into the LTE-A system.
The carrier aggregation technology refers to a mechanism in which User Equipment (UE) may simultaneously aggregate multiple cells and the multiple cells may simultaneously provide data transmission services for the UE. In a carrier aggregation system, carriers corresponding to the cells may be continuous or discontinuous in the frequency domain, to be compatible with the LTE system, the maximum bandwidth of each component carrier is 20 MHz, and the bandwidths between the component carriers may be the same or different.
Under the carrier aggregation, working cells of a terminal are divided into a Primary Cell (PCell) and multiple Secondary Cells (SCells), the primary cell is used for most control and signaling work, for example, sending uplink feedback of downlink data, reporting channel quality indicator (Channel Quality Indicator, CQI), transmitting uplink pilot carrier and the like, and the secondary cells are mainly used as resources for performing a data transmission function.
Component Carrier (CC) management may also be called cell management, and the concept is introduced based on a CA scenario. Under the CA condition, the CC management merely includes management on the secondary cells, for example, adding, modifying and deleting the SCells; but in a broad sense, management on the primary cell, for example, determining the PCell, changing the PCell and the like, may also be included in the scope of the CC management.
The CC management before release (Rel) 11 may consider a variety of factors, for example, a measurement result, load, interference and other factors. In the carrier aggregation system before R11, the CC management of the SCell is achieved by a radio resource control (Radio Resource Control, RRC) reconfiguration process; for the PCell change, it is achieved by a switching process.
The LTE network architecture is as shown in FIG. 1, a Mobility Management Entity (MME) is connected with an eNB through an S1-MME interface; the eNB completes an access network function and communicates with the UE through an air interface. There is one MME providing service for each UE attached to the network. The MME is called a serving MME of the UE.
A heterogeneous network deployment scenario including a Local eNB and a Macro eNB is as shown in FIG. 2. The Macro eNB provides macro coverage, and the Local eNB provides hotspot coverage within the macro coverage range.
For the network architecture as shown in FIG. 2, if in accordance with the existing mechanism, when moving within the Macro cell coverage range, the UE may continuously perform a switching operation between a Macro cell and a Local cell. In order to avoid data transmission interruption resulting from frequent switching, one manner is to separate bearers of a user plane and a control plane. However, in a bearer separation scenario, there is still no solution for managing cells controlled by a local node.
In summary, in a hierarchical network deployment scenario in which the user plane is separated from the control plane, there is still no solution for managing the cells controlled by the local node at present.